This invention relates generally to the field of cargo transport and more specifically to a device for support of transport container covers.
Open top containers used for transport of sundry types of goods or materials are common. Such containers generally comprise covers removable for loading or unloading and replaceable for transport.
These covers are often made of canvas, or other fabric, or fabric like material used to protect the container contents from the elements and to prevent the escape of contents out of the container. Said covers usually are supported in operative disposition by a framework which spans the open top while communicating with opposite sides thereof.
In example, U.S. Pat. No. 5,487,584 by Jespersen recites a series of parallel bows, each pivotably attached at one end along one side of the opening. The other end reversibly engages the other side of container top opening by means of a locking device. A perpendicular ridge pole is pivotably connected to each bow. This pole assures that all bows move in unison or are in unison prohibited from movement. One bow has a releasable locking mechanism. A pull on a rope releases the lock.
One end of each bow may pivot in a cylindrical hinge mounted oil the inside of the container. Alternately, the end of each bow may extend through the hinge through the floor of the container where a handle may be attached to pivot the bow. Or a bow may extend through the sidewall of the container where a handle, may be attached to pivot the bow. The cylindrical hinge is angled to cause the bow to lift slightly when it is pivoted from locked position.
The location of the Jespersen bow pivot hinges on the inside of the container exposes parts of the device to contact with cargo inside the ‘containers. This can foul or damage the device.
Jespersen requires the simultaneous release of the locking mechanism and initiation of pivoting movement. Jespersen requires the bows to swing simultaneously. They can move only in unison. Accordingly, the operator has no choice but to uncover the entire container from front to back. Jespersen additionally requires the operator to visually judge when bows are sufficiently rotated to provide a suitable opening such that loaded cargo will not contact the bows to cause damage to them.
In the Jespersen rope unlocking and pivoting embodiment; the operator must stand away from the trailer in order to minimize abrasion of the rope as it passes over the trailer edge and to achieve sufficient leverage to release the ‘lock and to move all bows at once. Also, the Jespersen structure that pivotably connects all bows is unnecessarily complex, comprising swivels and biasing elements to function with precision. When bent slightly or otherwise damaged by normal usage, it becomes difficult to operate and difficult to repair.
In example, the Jespersen bow pivoting operation requires assistance of gravity to complete final stages of a pivot process. The operator is thus not always in full control of bow movement. Also, if any hinges are fouled by exposure to the container contents, the gravity assist function may be hindered and the system rendered inoperable.
In addition, Jespersen requires that an end of the bows comprise an element which must slide into a receiving element mounted on the opposite wall of the container. Thus, the path of the rotating bow’ must be precise in order for said communication to be accomplished. Therefore a minimum of bending or distortion of the bows normally expected in the operation of such a cover system would render Jespersen inoperative. This is an inherent characteristic, although the receiving end is configured in such a way as to attempt to counteract it.
In the embodiment comprising an extended rod, the operator must first unlock the bows by means of the rope, secure the rope while maintaining tension to keep the lock open. The operator must then, while maintaining tension on the rope, simultaneously access the rotating handle below the floor of the trailer, which awkward process increases likelihood of injury.
In contrast, the instant art is operable from the ground without the operator having to move significantly away from the container or having to bend over or assume any other vulnerable position.
The instant art does not require a locking device or other receiving structure on an opposite wall to receive and/or lock a bow end.
The instant art does not require a release rope. The instant art does not require all bows to move at once; therefore, limited portions of the container may be opened as required, and less force is required to rotate elements of the cover support structure.
The instant art has no ridge pole or bias elements; therefore, the instant art is more simple and more easily repaired.
The instant art automatically restricts the range of bow rotation between open and closed positions. The instant art does not rely on gravity to assist motion; thus, the movement of the instant art is totally controlled by an operator.
The instant art pivoting and bow support means are never exposed to cargo inside the container.
Thus, the instant art overcomes these several disadvantages of Jespersen.